Question

The dome of a building is in the form of a hemisphere. Its radius is 63 dm. Find the cost of painting it at the rate of Rs. 2 per sq. m.

Answer 1

Surface area of a hemisphere = 2πr² 

Given, 

dome of a building is in the form of a hemisphere. Its radius is 63 dm. 

1 dm = 0.1m 

Thus, 

63 dm = 6.3 m 

Surface area of the dome = 2 × (22/7) × (6.3)² 

= 249.48 m² 

Cost of painting it at Rs. 2 per sq. m. 

= 249.48 × 2 

= Rs. 498.96